1. Technical Field
The present invention relates to a mobile terminal connectable to multiple radio communication systems employing different communication schemes, and a method for the mobile terminal to execute scanning for radio signals.
2. Description of the Related Art
Recently, radio communication systems such as cellular phone systems and wireless LAN systems are becoming popular. Accordingly, mobile terminals connectable to multiple radio communication systems employing different radio communication schemes are provided.
Such a mobile terminal connectable to multiple radio communication systems is required to detect a radio base station (access point) connectable from the location of the mobile terminal that changes frequently. Thus, the mobile terminal executes periodic scanning for radio signals transmitted from a radio base station constituting each radio communication system, to acquire notification (such as a scrambling code of the Code Division Multiple Access (CDMA) standard) contained in the radio signal.
A mobile terminal connectable to multiple radio communication systems is required to execute scanning for radio signals more frequently than a mobile terminal connected to a single radio communication system. This causes a drawback in increased electric power consumption and decreased available communication time and available standby time.
Hence, in order to solve the above problem, a method is known in which notification of a radio base station constituting a first radio communication system is included in a radio signal transmitted from a radio base station constituting a second radio communication system (e.g., see WO 04/091244, (p.p. 6 to 7, FIG. 1). According to such method, the mobile terminal only has to scan for a radio signal transmitted from the radio base station constituting a particular radio communication system, and thus electric power consumption can be reduced.
However, the above-mentioned conventional method includes the following problem. Specifically, in order to include notification of a radio base station constituting a first radio communication system in a radio signal transmitted from a radio base station constituting a second radio communication system, the method requires massive modification of an existing radio base station (or base station controller), such as changing a signal format transmitted by the radio base station.
The present invention has been made in view of the foregoing circumstances, and aims to provide a mobile terminal and a method for executing scanning for radio signals. The mobile terminal and the method are capable of executing scanning for radio signals transmitted from a radio base station at an appropriate timing, without modifying the existing radio base station or the like. Here, the mobile terminal is connectable to multiple radio communication systems employing different radio communication schemes.